Process of treating galvanized coatings



Feb. 9, 1937. J. L. scHUELr-:R Er AL 2,070,554

PROCESS OF TREATING GALVANIZED COAATINGS Filed May 6, 1935 @y eff Patented Feb. 9, 1937 PATENT oFFlCE PRocEss oF HEATING GALvANIzEn ooA'rlNGs Julian L. Schueler and Chalmer L'Heninger, Kokomo, Ind., assignors to Continental Steel Corporation, Kokomo, Ind., va corporation o! Indiana .Application May s, 1935, serial N0. 19,930

s claims. (ci. :a1-10.2)

.This invention relates to a treatment for a galvanized coating to be perfumed by preference when the coating is freshly applied while it is still in a molten state. Specifically we raise the with wires so treated indicates that there is lit- 5 5 temperature of such a coating, or at least maintain the coating in a fully liquid condition, and then impart thereto a sudden and brief chilling treatment in a manner which will produce benecial results. 'I'his has been performed successfully in connectionwlth continuous galvanizing operations on wires, wire fabrics, wire-fencing, etc., but may possibly with equal advantage be lapplied to sheets or articles which are galvanized by a semi-continuous or intermittent process.

In the ensuing description we shall explain our invention-in relation to the treatment of wires by way of example. It is well known that a sudden chilling of a coating freshly applied to a wire will produce an attractive appearance; There is usually the penalty, however, of an in creased liability for the coating to dust and to crack and peel from the wire, particularly when it is bent or fabricated. 4It is difficult, if not impossible, to chill such a coating for' the purpose ct obtaining a bright appearance without incurring ,some of the disadvantages just referred to.

According to our process the wire upon emerging from a bath of molten speltermay be moved through a high temperature zone to maintain the coating in a fully liquid .condition or even to further liquefy the coating. 'I'he wire is then passed immediately through a thin chilling curtain of water, steam, air or other gaseous medium. The speed of wire travel inl relation to the temperature o f this chilling curtainA and the thickness thereof is such as to prevent any substantial' chilling of the wire itself which forms the base for the coating. "This step-of coating 4ilconditioning may be carried out with a flame apparatus, as suggested in the Schueler Reissue Patent No. 19,209, wherein the coating is subjected to a constant imping'ement with the possibility of a progressively decreasing tempera- 45 ture; or it may be carried out with a heat treater, as suggested-in the Herman Patent No. 1,430,648, wherein there is no impingement and the temperature of the surrounding inert air is substantially uniform. These ,two treatments, while es- 60 sentially different, are'alike in the one respectV y that they serve to raise the temperatureof the` coating and increase its liquidity to a point somewhat above that which may obtain in the bath,

and hence are available in the practice of our 55 invention.

After this preliminary treatment which wel regard as desirable although perhaps notrnecessary in all cases, the coating on the wire is subjected to a sudden and brief chilling. `Experience tle or no dusting of the coating in consequence. The surface of the coating is rendered harder and better suited for various purposes. 1

As indicative of certain apparatus which is suitable for carrying out this invention, we have 10 shown in Figure 1 a longitudinal section through one end of a galvanizing bath adjacent which is a flame apparatus having at its exit end a means for producing athin water curtain;

Fig. 2 is a similar view in which a heat treater 16 is substituted for the iiame apparatus; and

Iig. 3 is an enlarged longitudinal view in section through the water curtain apparatus.

A number of wires w, arranged side by side,

may be passed through a galvanized bath B near 20 the exit end of which is a coating regulator R which removes dross, skimmings and coating in excess of that which is desired. Passing from the coating regulator the wire enters immediately 'into a flame apparatus F where the tem- 25 perature of the coating may be raised. If desired, the flame may be so controlled that the temperatures in this unit of the apparatus will progressively decrease toward the exit end. Im-

' mediately upon emerging from the flame appa- 30 `ratus the wire passes through a chilling medium C which we prefer should be in the form of a thin curtain of water. Substantially the same apparatus is shown in Fig. 2 where a heat Vrtreater H is substituted for the flame apparatus. 35

The chilling apparatus shown in Fig. 3 comprises a pipe p having connection with a. water source. Surrounding this pipe is a jacket j the ends of which are connected to a fitting f with an associated gland y and packing nut n. The space within thejacket is accordingly sealed at ever'y point.

Extending through the pipe, preferably `on its underside, 'are openings l through which water may enter the jacketed space. If desired, baiiles 5 may be arranged in the pipe to check the ow of wa'ter therethrough. The jacket is provided on 'jits'upper side with one or more orifices the form and arrangement of which may be varied as'found desirablel One such opening 6 may be' provided 50 adjacent each wire w as indicated at the leftend of Fig. 3; we may also employ two openings 1l having their axes converging .toward the proximate wire; and it may 'be feasible to use a narrow slit 8 extending in proximity to the adjacent wire, 55

`a point above the wires thereover.

or an elongated-slit 9 extending for a distance equal to the spacing between two or more wires, as indicated at the right end of Fig. 3. `Any one or more of those forms and arrangements of orices may beA employed. 'I'he jacketed pipe is arranged above a trough T having one or more drain openings d.

In operation a thin curtain of water is pro-- jected upwardly from the orice in the jacket to The water curtain proceeds both up and down, so as to contact with the wires at every circumferential point. The chilling effect, therefore, Ais sudden, brief and uniform. The speed of wire travel, perhaps 50 to 125 feet per minute, is such that the effect of chilling is conned to the coating alone. It does not penetrate through to the steel base upon which the coating is carried, or, at most, its effect will reach only the exterior'v surface of the base. I

At the moment that the coating is subjected to this brief chilling action, the temperature ofthe coating is considerably above its melting point. In fact, it may be several hundred degrees (Fahrenheit) thereabove. Whether or not this is responslble for the beneficial results we cannot say, but it is certain that the coating thus treatedis free from the detrimental effects of enhanced aking, chilling and dusting so common with coatings which are chilled by ordinary processes. We would have it understood, however, that the important point is not necessarily the raising ofthe coating temperature, but a maintained liquecation thereof up to `the moment that chilling takes place; and that the chilling itself, whether produced by water, air, steam or other medium, is

relatively sudden, brief and uniformly applied s'o as to affect the coating alone, or at most only the exterior surface of the base whereon the coating is carried.

We claim: y

1. In the art of continuously galvanizing wire by the hot dipping process, the steps of. advancing the wire with-*the appliedzinc coating still molten through a zone of relatively high temperaturel sufficient to raise the temperature of the molten coating to a point beyond that previously acquired, and thereafter immediately ad-A vancing the coating through a thin water curtain the temperature and volume of which in relation tothe speed of wire travel is so regulated as to chill the coating but not the wire base interiorly thereof.

2. In the art of continuously galvanizing wire by the hot dipping process, the lsteps of subjecting successive portions of a molten coating freshly applied to a wire while the wire is in longitudinal motion, to treatment by a regulator whereby to partially decoat the wire, in then subjecting successive portions of the coating of reduced amount while still molten to the action of heat suicient to raise further the temperature of the coating, and immediately thereafter in subjecting successive portions of the molten coating'so raised in temperature to a sudden chilling action whose intensity and duration is such as not to affect appreciably the temperature of the wire base to which the coating is applied.

3. In the art of galvanizing, the steps of subjecting an article upon which a zinc coating is still molten to the action of heat suicient to raise further the temperature of the coating, and immediately thereafter in subjecting the coating to a chilling action whose intensity and duration is insuicient to impart an appreciable chill to the article whereon the coating is carried..

JULIAN L, SCHUELER." CHALMER L. HENINGER. 

